{
  "alt": "Vertical bar chart of the percent change in births from 2018 to 2024 for six mother's age bands. The bars for the bands {fact:band_1519}, {fact:band_2024} and {fact:band_2529} are negative and get shorter with age, the bar for {fact:band_3034} is close to zero, and the bars for {fact:band_3539} and {fact:band_4044} are positive, with the oldest band the tallest.",
  "caption": "Bars for the three youngest bands lie below zero and bars for the two oldest lie above it, so the bars climb with age. The bar for mothers aged {fact:band_3034} is near zero and its interval includes zero. Each bar compares a band's births in 2024 with its births in 2018, pooled over the counties that publish the band in both years.",
  "data": [
    {
      "age": "15 to 19",
      "births_2018": 129757,
      "births_2024": 97772,
      "change": -24.65,
      "conf_high": -22.72,
      "conf_low": -26.53,
      "n_units": 577
    },
    {
      "age": "20 to 24",
      "births_2018": 527582,
      "births_2024": 439765,
      "change": -16.65,
      "conf_high": -14.98,
      "conf_low": -18.31,
      "n_units": 578
    },
    {
      "age": "25 to 29",
      "births_2018": 848726,
      "births_2024": 753795,
      "change": -11.19,
      "conf_high": -9.57,
      "conf_low": -12.87,
      "n_units": 578
    },
    {
      "age": "30 to 34",
      "births_2018": 910977,
      "births_2024": 920282,
      "change": 1.02,
      "conf_high": 2.65,
      "conf_low": -0.62,
      "n_units": 578
    },
    {
      "age": "35 to 39",
      "births_2018": 490705,
      "births_2024": 535630,
      "change": 9.16,
      "conf_high": 11.05,
      "conf_low": 7.32,
      "n_units": 578
    },
    {
      "age": "40 to 44",
      "births_2018": 103030,
      "births_2024": 123085,
      "change": 19.47,
      "conf_high": 22.34,
      "conf_low": 17.02,
      "n_units": 578
    }
  ],
  "id": "births_by_mother_age",
  "notes": [
    "The named counties are the {fact:counties_used} that CDC WONDER natality identifies in every year from 2018 to 2024: counties with {fact:wonder_threshold} or more residents in the population vintage WONDER uses, which is earlier than the 2020 Census. WONDER pools the births of every other county in a state into one row, so those counties are not in the named counties.",
    "Intervals are 95% intervals from a bootstrap over counties (replicates and seed in the methods note). Births are full counts, so an interval shows how much a pooled figure depends on which counties are in the group, not sampling error in the counts.",
    "WONDER splits births into nine age bands. Mothers under {fact:age_15} and mothers {fact:age_45} and over are left out because WONDER withholds most of those cells; the methods note gives the counts. A withheld cell is missing, never zero, and a county that withholds a band in 2018 or 2024 is left out of that band's bar; the data table gives the number of counties in each bar."
  ],
  "source": "CDC WONDER natality, births in 2018-2024; full counts of births by mother's age; changes pooled over counties; intervals from a bootstrap over counties",
  "spec": {
    "category": "age",
    "categoryLabel": "Mother's age (years)",
    "colors": {
      "negative": "highlight",
      "positive": "accent"
    },
    "diverging": true,
    "domain": [
      -30,
      25
    ],
    "format": {
      "digits": 1,
      "signed": true
    },
    "orientation": "v",
    "sort": "data",
    "value": "change",
    "valueLabel": "Change in births, 2018 to 2024 (%)"
  },
  "subtitle": "Pooled change in live births by mother's age band, 2018 to 2024, in the {fact:counties_used} named counties, with 95% intervals from a bootstrap over counties",
  "title": "Births fell for mothers aged {fact:band_1529}, changed little for mothers aged {fact:band_3034} and rose for mothers aged {fact:band_3544} from 2018 to 2024",
  "type": "bar",
  "width": "body"
}